Dust is an ongoing problem at construction sites. Composite building products—grout and mortar, for example—are often made from at least one powdered material that emits dust when it is handled. Dust suppressants are currently available, but they do not fully eliminate dust production and they add an additional ingredient to the process.
Composite building products are often made from three components: (1) a thermoset resin, (2) a hardener, and (3) a filler. The filler provides bulk and other performance characteristics to the product. In grout or mortar, for example, the filler is often sand. The thermoset resin and the hardener chemically react when mixed, creating a structural matrix in which the filler is dispersed. This is commonly called a reactive binder system. The end product—after the filler is mixed in—is often a grout or mortar, which is initially highly malleable and, upon curing, becomes extremely hard, rigid, and durable.
The filler material typically generates a significant amount of dust when it is handled and manufactured, which tends to cause problems as it spreads throughout the environment. For instance, the generated dust can harm machines, furniture, and people; cause local air quality violations; and require excessive cleanup. Further, any dust that escapes the mixing process is wasted material. Accordingly, reducing dust has been a longstanding goal in the construction industry.
The countermeasures currently available typically require adding an extra ingredient to the reactive binder system as a dust suppressant. For example, U.S. Pat. Nos. 8,974,595 B2 and 5,595,782 describe adding various oil-based substances, including vegetable and mineral oil, to a dry composition in an attempt to reduce dust emissions. In addition, U.S. Pat. No. 5,328,497 describes applying a lignosulfonate composition to fertilizer to prevent dust. Further, U.S. Pat. No. 5,194,174 describes methods for controlling dust by applying water-based solutions, including polyvinyl alcohol, to dust-producing materials.
Yet, these solutions are unsatisfactory for a number of reasons: First, introducing a new ingredient to a composite product complicates the process. The new ingredient might degrade the end-product's quality or interfere with the reactive binder process. For example, mineral oil can cause a plasticizing effect on the reactive binder system, reducing its overall strength. Thus, the user must determine whether the dust-suppressant is compatible with the other ingredients before using it.
Second, using an additional ingredient creates an added cost to produce the composite building product. Finally, the current dust suppressants do not effectively eliminate dust during manufacturing procedures.